SEOUL, Sept. 22 (Yonhap) -- Typhoon Tapah was moving north toward the southern island of Jeju on Sunday, the weather agency said, with heavy rains and strong winds already battering the island and other southern regions and causing cancellations of hundreds of flights.

The powerful typhoon, packing wind gusts of 126 kph with an atmospheric pressure of 970 hectopascals at its center, was about 330 kilometers southwest of Jeju traveling at a speed of 20 kph as of 6 a.m., according to the Korea Meteorological Administration (KMA).

The typhoon is expected to pass about 130 km southeast of Jeju around noon and 170 km southwest of the southeastern city of Busan at around 6 p.m. The closest it is expected to be to Jeju is forecast to be 90 km at around 3 p.m., while it is expected to be closest to Busan around 10 p.m. at 50 km.

The interior and safety ministry upgraded the weather alert level to "vigilance" from "attention" Saturday as the typhoon is expected to seriously affect the country's southern region.

Parts of Jeju had received 371.6 millimeters of rain and Sancheong county in South Gyeongsang Province reported 118.5 mm of rainfall as of 6 a.m., the weather agency said.

In Busan, a two-story old house collapsed Saturday, killing a 72-year-old woman who lived on the first floor.

The large glass window of a building in Busan was shattered by strong winds and fell on the sidewalk below. But there were no reported casualties.

Some 200 households also suffered a power failure Saturday night as a makeshift installation at a construction site hit an electric cable when it fell down due to gusts.

The KMA warned that strong winds and heavy downpours are expected to hit Jeju Island, parts of the southern areas and the country's easternmost islets of Dokdo.

"There is a need to thoroughly brace for the typhoon in coastal and inland areas as serious damage is expected," a weather agency official said.

According to the transport ministry, 489 flights were expected to be canceled across South Korea on Sunday due to the typhoon, beginning with Asiana Airlines Flight OZ8900 scheduled to depart from the southern island of Jeju for Seoul's Gimpo at 6:30 a.m.

More cancellations are expected later in the day as the typhoon approached the country, the ministry said.

"Passengers are advised to make sure their flights remain on schedule before leaving for airports," a transport ministry official said.